Questions tagged [lidar]

LIDAR (Light Detection and Ranging or Laser Imaging, Detection and Ranging) is an active optical remote sensing technology that measures properties of scattered light to find range and/or other information of a distant target.

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2
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1answer
505 views

How to write multiple .las files from polygon clipping with PDAL?

I am using PDAL (through Python) to crop multiple polygons from a point cloud and store them as separate files. For efficiency reasons I would like to define this in a single pipeline. However, using ...
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2answers
300 views

Merging LiDAR tiles without losing data in QGIS?

I'm trying to merge some LiDAR tiles together but when I do, the clarity of the image drops, so I think that means I am losing some data. How do I merge the tiles and keep all of the data and the ...
7
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2answers
187 views

Prevent SAGA in QGIS 3.0 from creating certain outputs?

I'm wondering if there is a way to prevent SAGA from generating temporary files. For example, if I just want to generate a slope map using SAGA I have to wait for all 11 other grids to get processed. ...
4
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1answer
176 views

Importing multiple .asc files into PostGIS violates check constraint. Why?

I am importing thousands of .asc files into PostGIS into this table: CREATE TABLE stg.COUNTRY_1M(rid serial primary key, rast raster); CREATE INDEX ON stg.COUNTRY_1M USING gist (st_convexhull(rast)); ...
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2answers
72 views

Locate LAS Points By Proximity gives ERROR 999999?

I am trying to locate LAS points which is within a specific distance (25cm or 50cm) from the 3D points in a feature class. This is exactly what the Locate LAS Points By Proximity tool should do. My ...
2
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1answer
470 views

Converting DEM to LAS file? [duplicate]

Is there a way to convert a DEM raster to a .las file using open source software and/or any tools that come along with a complete ESRI license? I have been able to achieve this using the LAS Toolset ...
2
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1answer
666 views

How to import raster (.asc) data to PostGIS?

I am using Postgres 10.3 / Postgis 2.4.2, and I have thousands of ".asc" files (LiDAR DTM/DSM files) to import to the db. However, the format is something like: ncols 1000 nrows 1000 xllcorner ...
3
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1answer
171 views

Extracting only elevation data from NASA's GLAS Satellite LiDAR to create raster DEM?

I'm trying to open data downloaded from NASA's Earthdata site in ArcGIS 10.4.1. Specifically I'm trying to open "GLAS/ICESat L2 Global Land Surface Altimetry Data (HDF5) V034" (Image below, ...
5
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1answer
130 views

How to assign (or project) CRS to LiDAR file in lidR?

Can someone enlighten me if there is a difference between initializing a CRS object using the EPSG code versus just the +proj string read from a shapefile? Consider the following objects: A ...
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2answers
203 views

GRASS r.in.lidar (las to raster) inside Python loop?

I have a loop in Python to list out LAS files in a folder, and run two commands in Grass GIS on these files to write them out as rasters. The loop runs but at the end I get an arg must be string not ...
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2answers
482 views

Clipping object of class LAS with polygon shapefile using lidR?

I want to make a simple clip with my .las 3D-Pointcloud. Therefor I use the lasclip() function. Import .las: lidar <- readLAS("~/data.las") lidar gives me class : LAS (LASF v1.2) memory ...
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1answer
112 views

Batch processing LiDAR files (.las to raster) with PyQGIS?

for layers in glob.glob("*.las"): processing.runalg("grass7:r.in.lidar", "input_las",5,1,"",1,100,"","",5,"","",False,True,True,"331289.57265,337990.42735,4558790.0,4560890.0",0,layers+"E:/...
6
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1answer
2k views

numpy array to GTiff using rasterio without source raster

I have a numpy array that represents rasterized data from a LiDAR point cloud. For example: import numpy as np import rasterio arr = np.random.randint(5, size = (100, 100)) I know information about ...
0
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1answer
104 views

Batch scripting r.in.lidar in pyQGIS for LiDAR DEM output? [duplicate]

I need to use pyQGIS to write a script that will run the r.in.lidar GRASS 7 on a set of LAS files. I am terrible at Python, but I need this for my task. I would like to process as a batch. How can I ...
0
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1answer
55 views

access r.in.lidar through pyGIS console [duplicate]

How can I access the r.in.lidar algo with the pyqgis console? i tried to import processing and algolist but r.in.liad under the GRASS GIS algo does not get listed. Also Checked the options iunder ...
5
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1answer
348 views

Georeferencing terrestrial LiDAR point cloud?

Recently I took a Faro Focus terrestrial laser scanner to a forested area and collected multiple scans for 12 fixed radius plots. Each plot had 5 GPS points collected within it in hopes to ...
2
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2answers
65 views

Correcting merged LiDAR DEM with outliers in inner edges?

I've created a DEM from LiDAR data. After combining all the files, I could see that there are some problems through the tile borders. This is an screen focused in one of the cross section of 4 files ...
2
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2answers
123 views

Why such a large difference between overlapping LiDAR DEM values?

Background: Using Arc Desktop 10.5.1, I have been tasked with mosaicking two adjacent LiDAR rasters (I'll call them A and B). They were flown, processed and supplied under contract by different ...
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0answers
126 views

Create laspy file object without creating a new file

I would like to create a new laspy.file.File object in memory without having to create a reference .las file. The basic procedure is read sample.las clip sample.las by converting the x and y ...
2
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1answer
160 views

Preventing interpolation outside of data extent with LAS Dataset To Raster ArcMap?

When I use the LAS Dataset To Raster tool in ArcMap I get an unwanted interpolation outside of the actual study area, like this: According to Esri this can be prevented by changing the definition of ...
5
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1answer
149 views

Fixing spikes in DSM from LiDAR?

I have a DSM derived from drone LiDAR that I want to use as a base to drape imagery and, paired with a DTM, as a basis for estimating canopy height/volume. Unfortunately, the DSM has has many "spikes"...
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1answer
231 views

Visualizing LAS with matplotlib

I'm trying to create a 3D scatterplot using an las file that contains xyz and return values. I want to keep all returns but would like to subset the cloud. I've learned how to subset using laspy so no ...
3
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1answer
240 views

Displaying LiDAR data with too many points in ArcMap?

I have imported LiDAR data into ArcMap in the shape of a Las DataSet with twelve .las files (contains over 100 million data points). I believe the file itself is working properly. However, no points ...
5
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1answer
352 views

GRASS's r.in.lidar error in QGIS 3: “North must be north of South”

I have LAZ files that I unpacked with laszip.exe, then I ended up with LAS files. These files showed no error when making a LAS dataset in ArcGIS. I used this dataset several times without ant issues....
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1answer
207 views

Locating outliers in LAS Dataset with ArcGIS?

According to the statistics and symbology of my LASD I have outliers. See below: How can I locate them in ArcGIS 10.x and do further analysis with them? I cannot query the dataset or select point? So ...
4
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1answer
142 views

Setting GroundFilter parameters for low density point clouds?

I'd like to use the function GroundFilter on my dataset. However, the manual says that the default values of the parameters used by this function (g parameter, w parameter) are related to a high ...
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0answers
176 views

Visualizing LiDAR data in a detailed footprint of rooftops with ArcGIS [closed]

For the last couple of weeks, I have been doing a research for making a detailed footprint with LiDAR data. The detailed footprint is needed for visualizing a 3D model. With a detailed footprint I ...
7
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2answers
5k views

Installing LAStools in QGIS 3.0?

I don't know how to install LAStools in QGIS 3.0. In QGIS 2.18, you can incorporate it as a provider in Processing -> Options-> Tools for LiDAR data (for example: Installing LAStools in QGIS 2.4?). ...
4
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1answer
240 views

Cropping raster and merge it to overlapping DEM?

I am working with an existing DEM of a river and its surrounding area in QGIS (actually a virtual raster from four separate DEM TIF tiles). My goal is to add a bridge's profile to the DEM. I have a ...
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0answers
90 views

Rice Field Levee Contours - .2 foot interval needed - LiDAR data? [closed]

I am a rice farmer in Arkansas and would like to create levees along contour lines in a field at a .2 foot interval. How could I utilize LiDAR data to map 0.2 foot contour intervals across my area of ...
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0answers
151 views

FUSION's PolyClipData creates corrupt LAS file?

I am trying to learn LASPY and am following a tutorial. I got an error when starting up using: import laspy infile = laspy.file.File("./laspytest/data/simple.las", mode="r") where I got a storage ...
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2answers
918 views

laspy ValueError: buffer size must be a multiple of element size

I am trying to learn LASPY and am running into road blocks off the bat. I first ran into and Error 8 (Not enough storage is available to process this command) using my full sized LAS file (1.7GB). I ...
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1answer
117 views

Which QGIS installation for Windows comes with r.in.lidar?

I am running QGIS 2.18.14 (QGIS code revision: ff83b9a479) on a windows 7 machine, it comes with GRASS 7.2.2 (Code Revision r71496), but it does not come with r.in.lidar. I have noticed QGIS 2.18.16.1 ...
2
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1answer
41 views

How does MERIS collect vegetation height data?

In GlobCover 2005 and 2009 project, the sensor used for spectral data collection was MEdium Resolution Imaging Spectrometer (MERIS). It observes the Earth in 15 spectral bands in visible and near ...
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8answers
3k views

Editing LiDAR point cloud to remove noise/outliers present below and above ground?

I have "dirty" LiDAR data containing first and last returns and also inevitably errors under and over the surface level. (screenshot) I have SAGA, QGIS, ESRI and FME at hand, but no real method. What ...
4
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2answers
327 views

How to filter point cloud by flightline in R?

The lidR package in R provides a way to mark individual points in a point cloud with a flightline ID by using lasflightline(). From the documentation: Retrieve each individual flightline by ...
2
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1answer
99 views

How to incorporate stdmetrics in gridmetrics function?

I am attempting to feed the lidR gridmetrics function a list of metrics. I can generate the list of metrics within a function (following this example): myMetrics = function(z, i) { metrics = list( ...
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1answer
138 views

Classify LAS By Height tool is not yielding any results?

The classify LAS by height tool (CLHT) in ArcGIS says that it will only reclassify LAS points with class codes of 0 or 1 (http://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/classify-las-by-...
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2answers
102 views

Getting statistics in cross sections at varying heights in LAS files?

I am looking to cross section my forest at varying heights. I have high return LAS data (8 points/m2 and average point spacing of 0.2m) and I am looking to do more than the simple 1, 2, 3 approach of ...
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0answers
83 views

Completing Coordinate transformation?

I have two airborne lidar datasets and, for purposes of comparing change between the two, would like to standardize the vertical and horizontal coordinate information for each. The plan is to ...
3
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1answer
535 views

error: Compression support not enabled in liblas configuration

I am using liblas 1.8.1 and laszip 3.1.1 on Mac OS High Sierra. Both were installed using brew install <package>. I am looking to get information from a laz file using the following command: ...
4
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3answers
579 views

Open source approach to classifying and removing LiDAR points from overlapping scans?

The attached screenshot shows a LiDAR point cloud with significant overlapping scans. This point cloud tile is part of the MN statewide LiDAR dataset which has 25% scan overlap and 1.5 NPS. For many ...
0
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1answer
308 views

Difference between files of extension .asc, .asc.aux.xml, .aux and .rrd?

I have received ASCII data from a client. These ASCII files have been created from LiDAR data. For each tile there are 4 different file types: Filename.asc Filename.asc.aux.xml Filename.aux ...
3
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0answers
51 views

Checking and enforcing downstream Z constraint for synthetic streams?

Assume I've delineated planar (X, Y) stream breaklines to use them for enforcement of bare ground DEM derivation from high density lidar data. The stream features are in a Z and M enabled polyline ...
6
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1answer
412 views

Laspy exception: “Invalid format”

I am attempting to open a couple of las files in laspy, however one of them has file version 6.0 (although it does not show up as such in lasinfo - I may be missing something). Digging through the ...
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1answer
116 views

PDAL: Argument references invalid/unused stage: 'filters.voxelgrid'

I am running into an error when running pdal translate on Mac OS High Sierra: PDAL: Argument references invalid/unused stage: 'filters.voxelgrid'. This is the command I am using based on a PDAL ...
2
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2answers
221 views

Interpolating LiDAR scattered ground data?

I wonder if someone can give me a hint on how to interpolate sparse data. I have a 1km by 1km tile located in a dense rain forest area. Original LiDAR data are 37,395,021 points. I have played with ...
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0answers
436 views

Generate Height map for unity-3D from Lidar point data [closed]

I have Downloaded a data set from udacity open source self driving car program from here. It is a ROS (Robotic operating system) BAG file more info.The BAG file contains data collected from Velodyne ...
2
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2answers
120 views

Finding pixels in DEM with 5% slope or less? [closed]

I am trying to determine if a given property may be amenable for a ground based commercial solar project. Among basic requirements there is flatness (5% slope or less), so I am trying to determine ...
1
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1answer
33 views

SPDLib spdinterp Error: Two file paths should have been specified (e.g., Input and Output)

I am using spdinterp from the SPDlib to produce a digital terrain model using the following command: spdinterp --dtm --topo -r 50 -c 50 --overlap 10 -i NATURAL_NEIGHBOR -f HFA -b 1 /Users/aaron/data/...